JP2005331641A5 - - Google Patents

Claims (14)

In order from the object side to the image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power and a positive third lens group refractive power, zooming by changing the distances between the lens groups In the zoom lens, the first lens group has one negative lens and one positive lens, and the second lens group has one positive lens and one negative lens, The third lens group has one positive lens, and with respect to the position in the optical axis direction, the object-side vertex of the lens disposed closest to the object side of the second lens group, and the object-side surface of the lens A zoom lens comprising an F-number determining member for determining an open F-number light beam between intersections with an outer peripheral portion.   The lens disposed closest to the object side of the second lens group is a positive lens having a convex surface on the object side, and the object side surface of the positive lens is a positive lens in the second lens group. 2. The zoom lens according to claim 1, wherein the absolute value of the radius of curvature is the smallest.   The first lens group includes, in order from the object side to the image side, a negative meniscus lens having a convex object side surface and a positive meniscus lens having a concave image side surface. 1 or 2 zoom lens.   4. The second lens group includes a cemented lens of a positive lens and a negative lens in order from the object side to the image side, and a lens having convex surfaces on the object side and the image side. Zoom lens.   During zooming from the wide-angle end to the telephoto end, the first lens group moves along a convex locus toward the image side, the second lens group moves monotonously toward the object side, and the third lens group moves toward the image side. The zoom lens according to claim 1, wherein the zoom lens moves. The distance in the optical axis direction between the object-side apex of the lens arranged closest to the object side of the second lens group and the F-number determining member is D2S, and the lens arranged closest to the object side of the second lens group When the distance in the optical axis direction between the object-side vertex and the intersection between the object-side surface and the outer periphery of the lens is D2R,
0.2 <D2S / D2R <0.9
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. The distance between the image-side vertex of the first lens group and the object-side vertex of the second lens group at the zoom position at the telephoto end is L1T, and the object-side vertex of the lens disposed closest to the object side of the second lens group When the distance in the optical axis direction from the F number determining member is D2S and the focal length of the entire system at the zoom position at the telephoto end is ft,
0.02 <(D2S + L1T) / ft <0.08
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the focal length of the first lens group is f1, and the focal length of the entire system at the zoom position at the wide angle end is fw,
-2.6 <f1 / fw <-1.6
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the focal length of the second lens group is f2, and the focal length of the entire system at the zoom position at the wide angle end is fw,
1.2 <f2 / fw <2.0
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. The distance from the object-side vertex of the lens disposed closest to the object side of the first lens group to the image-side vertex of the lens disposed closest to the image side of the first lens group is DL1, and the distance of the second lens group The distance from the object side apex of the lens arranged closest to the object side to the image side apex of the lens arranged closest to the image side of the second lens group is DL2, and the distance from the object side apex of the third lens group is arranged closest to the object side. When the distance from the object-side vertex of the third lens to the image-side vertex of the lens disposed closest to the image side of the third lens group is DL3, and the focal length of the entire system at the zoom position at the wide-angle end is fw,
1.3 <(DL1 + DL2 + DL3) / fw <2.0
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.   11. The zoom lens according to claim 1, wherein focusing is performed from an object at infinity to an object at a short distance by moving the third lens group toward the object side. When the focal length of the lens located closest to the object side of the first lens group is f11, and the focal length of the lens located closest to the object side of the second lens group is f21,
−1.6 <f11 / f21 <−0.8
The zoom lens according to claim 1, wherein the zoom lens satisfies the following condition.   The zoom lens according to claim 1, wherein the zoom lens is an optical system for forming an image on a solid-state imaging device.   An image pickup apparatus comprising: the zoom lens according to claim 1; and a solid-state image pickup device that receives an image formed by the zoom lens.